Coal dust furnace for high pressure boilers



5 zfe oan We)" IN TDIT Filed Sept. 20, 1928 S LGFFLER COAL DUST FURNACEFOR HIGH PRESSURE BOILERS July 7, 1931.

1 Fig.1. The furnace gases-can,

' .45 horizontal or transverse tu Patented July 7, 1931 PATENT OFFICEs'rnzrmn 1611mm, OI. f-dnannor'rnmmno, NEAR BERLIN, GERMANY; JENNY EL-rnmnn Lori-LE2. sonn nm AND OF SAID STEPEAN IJi FFLEB, DECEASED GOALDUST FURNACEFOR HIGH PRESSURE BOILERS Application filed September 20,1928, Serial No. 307,289,, and in Germany September 26, 1927.

This invention relates to a coal dust furnace intended for use inconnection with h1ghpressure boilers, especially such as shown anddescribed in my U. S. A.- application Serial Number 701,855, filed March25, 1924.

The chief characteristic feature of the present improved furnace residestherein that there are arranged in the furnace U-shaped superheatingtubes branching oft from upper collecting tubes and forming with theirvertical legs bounding walls for'and in the furnace space, thehorizontal or transverse legs extending in several heights and affordingfree passages for the furnace gases on their way to flue or fluesprovided in the boiler.

The invention is illustrated diagrammatically and by way of example onthe accompanying drawin s on which Figure 1 is a vertical section trough a coal dust furnace designed according to this invention, andFigure 2 shows a detail, all as fully described hereinafter.

On the drawings, 1' (Fig; 1) denotes the 26 furnace space, and 2 are U-aped superheat- ..ing tubes arranged therein. The tubes 2 are branchingoff from upper collecting tubes 3 and 4, and their vertical legs aresoarranged with respect to one another that they form a bounding wall orparts of such wall. That is to say: either said vertical tube legszhemselves, i.e. solely these tube legs, for1 1 said wall, in that theyare arranged 'sufiiciently closely to one another, or the said legs areprovided with lateral ledgesj5 (Fig. 2), or'

instead of these ledgis br cks of refractory clay are arranged tween thesaid legs. These latter extend in any case down to about the depthar-a,below which the hori- 0 zontal or transverse connecting arts ofthesuperheating legs 2 are locate in several 'helghts or depths, forinstance in three, as in therefore,

aps between these ortions to the lines which form parts of t e furnace,as

shown.

There are two furnace-forming flues 15 and 16 in the example shown, andcoiled pipes 6 D0 and 7 are arranged in these flues, of which "passthrough the spaces or the flue 15 contains an aftersuperheater 6 and afeed-water heater 7, and the flue 16 contains a feed-water heater 7which is connected up in series with the feed-water heater 7, as shown;the flue 16 contains, besides, an air preheater 12. The steam to besuperheated is produced in the drum-shaped boiler 8 and conveyed to thesuperheatingtubes '2 by means of pipes 17 and 18, and by a pump 9inserted between these pipes, as shown. There may be individual tubes 2connected up in parallel, as in the drawing, but the tubes may becombined to a plurality of nests which in turn may be connected up alsoin parallel or in series or partly in parallel and partly in series, asmost suited in the given case. The superheated steam flows through thepipes 4 andlO to the after-superheater 6 and finally through the pipe 11to and into the boiler 8, as well as to a pipe D through which a part ofthe superheated steam is conducted to an engine, whereas the other partis used for the generation of live steam in the boiler 8.

The feed water is supplied at b and passes through the feed-waterheaters 7' and 7 in the direction indicated by the arrows. The heatedwater then flows through the pipe 19 to and into the boiler 8, in whichit is converted into steam bya part of the super-v heated steam arrivingthrough the pipe 11, as already mentioned.

I- wish it to be understoodthat the feedwater heating coil 7 may bedispensed with, in which case the feed-water heating coil 7 is, however,correspondingly longer or larger. In either case an air heater 12 ispreferably arranged in the flue 16, and the air which is supplied tothis heater at A is used for operating the dust coal burner 13 which isconnected at 14 by means of a pipe 20'(indicated only by dotted lines)with the air-heater 12, and receives'the dust coal through the pipe 121. 22 denotes the-waste gas flue.

-I claim: 1

1. A dust coal furnace of the Loflier type, comprising, in combinationwith the furnace parts forming the combustion space, and with the meansfor introducing the dust coal into said space, downwardly extending U-shaped superheating pipes arranged in said space and forming'with onehalf of their legs a bounding wall between the said space and aneighboring space in said furnace, the

5 transverse pipe parts connecting said wallforming regs with theopposite other legs being arranged in different heights so as to formpassages between them, substantially and for the purpose set forth.

2. A dust-coal furnace, comprising, in combination, with the means forintroducing the dust-coal into the combustion space, downwardlyextending U-shaped super-heating pipes forming said space, thetransverse pipe parts connecting one set of the legs of said pipeswith-the opposite set thereof bein arranged in different heights so asto 1 orm passages between them, said transverse pipe "parts being freelyarranged in the combus- 0 tion chamber to accommodate free expansion andcontraction of the legs of th pipes.

' 3. A dust-coal furnace, comprising, in combination, with means forintroducing the coal-dust into the combustion chamber, down- 5 wardlyextending U-shaped super-heating pipes forming said space, each U-shapedpipe including opposed leg parts and a connecting part for'iningthe soleconnection between the leg parts, said connecting parts being arrangedat different heights to form passages I therebetween and being freelyarranged in the combustion chamber to accommodate free expansion andcontraction of the leg parts of the pipes.

In testimony whereof I aflix my signature.

ISTEPHAN LOFFLER.

